Extension Lead Load Calculator
High-draw appliances like kettles, heaters and hairdryers can add up quickly on a single extension lead, and it's easy to underestimate the combined load. List what you're planning to plug in below and we'll check the total against your lead's safe rating.
Check your extension lead load
List what you want to plug in and we'll check it against your lead's safe rating.
Total load: 4,200W of a safe maximum of 2,990W on a 13a lead (standard uk)
Overloaded by 1,210W — split these across more than one lead/socket.
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A few well-reviewed extension leads and electrical accessories.
£6.99
Pros
- Cheap way to confirm a socket or fitting is dead before working on it
- Slim pocket size for a tool bag or van door pocket
- Detects both live and neutral wires
Cons
- Neon indicator can be hard to see in bright daylight
£9.50
Pros
- Trusted UK brand fitted as standard by many electricians
- Inherent antimicrobial properties on the faceplate
- Neat white moulded finish matches most existing sockets
Cons
- Must be fitted by, or notified to, a qualified electrician under Part P
£34.00
Pros
- Combined breaker and RCD protection on a single circuit
- Compatible with Schneider Resi9 consumer units
- Reduces nuisance tripping compared with a shared RCD
Cons
- Installation must be carried out by a registered electrician
Frequently asked questions
What happens if I overload an extension lead?
An overloaded lead carries more current than it is rated for, causing the cable to heat up. This can trip a circuit breaker as a safety measure, but sustained overloading — especially on a coiled or covered lead — is a genuine fire risk.
What is a standard UK extension lead rated at?
Most household extension leads are rated at 13A, matching a standard UK plug, which gives a safe maximum of around 3000W (13A × 230V). Heavy-duty or site/trade leads are often rated at 16A for higher-draw equipment.
Should I always uncoil an extension lead before use?
Yes — a coiled lead traps heat and can overheat even well within its rated wattage, particularly with high-draw appliances like heaters or kettles. Always run the lead out fully before use.
Can I plug an extension lead into another extension lead?
Daisy-chaining extension leads is not recommended. It makes it easy to unknowingly exceed the rating of the weakest lead in the chain and increases the risk of a loose or overheating connection.